For tracing a new house and tracing wires on CNC machines. Great for that. It has RJ 11 but it connects perfectly to RJ 45. Alligator leather clips are good too. Use a stripped piece of coax cable to attach it to the center pin to trace the cable lines as well. Not sure why some say it's weak as I'm tracking a 5400 square foot house with drops everywhere and have had no trouble tinting long runs. I just made sure I bought good quality batteries. Cheap batteries will never work as well in this type of device. I'm running lithium 9v. I've disassembled both units and the electronics are clean and sufficient. The only thing I would like to criticize is that the case is made of very poor plastic. For the money they thought they had already paid for it. I will buy again. I would recommend for a starter kit or if you have employees and don't want to send expensive tools out in the field. Also great for homeowners.